Self-identifying solid-state transducer modules and associated systems and methods

ABSTRACT

Self-identifying solid-state transducer (SST) modules and associated systems and methods are disclosed herein. In several embodiments, for example, an SST system can include a driver and at least one SST module electrically coupled to the driver. Each SST module can include an SST and a sense resistor. The sense resistors of each SST module can have at least substantially similar resistance values. The SSTs of the SST modules can be coupled in parallel across an SST channel to the driver, and the sense resistors of the SST modules can be coupled in parallel across a sense channel to the driver. The driver can be configured to measure a sense resistance across the sense resistors and deliver a current across the SSTs based on the sense resistance.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/626,979, filed Jun. 19, 2017; which is a continuation of U.S.application Ser. No. 15/074,276, filed Mar. 18, 2016, now U.S. Pat. No.9,723,672; which is a continuation of U.S. application Ser. No.14/625,501, filed Feb. 18, 2015, now U.S. Pat. No. 9,293,638; which is acontinuation of U.S. application Ser. No. 13/596,437, filed Aug. 28,2012, now U.S. Pat. No. 8,963,438; each of which is incorporated hereinby reference in its entirety.

TECHNICAL FIELD

The present technology relates to solid-state transducer (“SST”)modules. In particular, the present technology relates toself-identifying SST modules and associated systems and methods.

BACKGROUND

Mobile phones, personal digital assistants (“PDAs”), digital cameras,MP3 players, and other electronic devices utilize light-emitting diodes(“LEDs”), organic light-emitting diodes (“OLEDs”), polymerlight-emitting diodes (“PLEDs”), and other SST devices for backlighting.SST devices are also used for signage, indoor lighting, outdoorlighting, and other types of general illumination. FIG. 1A is across-sectional view of a conventional LED die 10 that includes asubstrate 12 carrying an LED structure 14. The LED structure 14 has anactive region 16, e.g., containing gallium nitride/indium galliumnitride (GaN/InGaN) multiple quantum wells (“MQWs”), positioned betweenN-type GaN 18 and P-type GaN 20. The LED die 10 also includes a firstcontact 22 on the P-type GaN 20 and a second contact 24 spacedvertically apart from the first contact 22 on the front surface of theN-type GaN 18. The second contact 18 typically includes a transparentand conductive material (e.g., indium tin oxide (“ITO”)) to allow lightto escape from the LED structure 14. In other conventional LED devices,the first and second contacts 22 and 24 are spaced laterally apart fromone another on the same side of the LED structure 14 and/or bothcontacts 22, 24 may be positioned at the back side of the LED structure14.

LED dies (e.g., the LED die 10 shown in FIG. 1A) can be coupled togetherin an LED module and connected to an LED driver to form an LED lightfixture or luminaire. For example, FIG. 1B is a partially schematiccross-sectional view of a conventional LED module 30 including asubstrate 32 carrying a plurality of LED dies 10, a converter material34 (e.g., phosphor) that manipulates the color of light emitted by theLED dies 10, and an encapsulant or lens 36 over the LED dies 10. The LEDdies 10 are connected to a common anode and cathode, which are in turncoupled to an LED driver 38 (shown schematically) that can supplycurrent to drive the LED module 30. Additional LED modules 30 can beelectrically coupled to the LED driver 38 in an LED light fixture orluminaire.

LED drivers are typically selected based on the quantity of LED modulesin the luminaire and/or the operating parameters of the individual LEDmodules such that the driver supplies the appropriate level of currentacross the LED modules. If a change is made to the number of LED modulesin a luminaire, a new driver must be matched to the new configuration.Accordingly, LED manufacturers must stock numerous LED drivers withincrementally increasing voltage and current outputs to match differentluminaire configurations. Modifications to the circuitry connecting theLED modules to the driver may also be made to distribute the appropriatelevel of current across the LED modules. For example, a change in thenumber of LED modules may require an engineer to determine theresistance that needs to be added to the circuit to accommodate thespecific configuration of the luminaire, and then the appropriateresistor must be added in the LED circuit.

Other LED luminaires include what is known as an “intelligent driver”that can recognize changes in the quantity or type of LED modules in theluminaire and adjust current output settings accordingly. Such driversinclude switch mode power supplies, dedicated analog circuits, and/ordedicated memory circuits (e.g., flash memory) that identify the LEDmodule configuration of the luminaire and adjust the current outputaccordingly. However, because LED drivers are already one of, if not themost expensive component in LED luminaires, the complex features ofintelligent drivers only further increases the overall manufacturingcost of LED luminaires.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a partially schematic cross-sectional diagram of an LED dieconfigured in accordance with the prior art.

FIG. 1B is a partially schematic cross-sectional diagram of an LEDmodule configured in accordance with another embodiment of the priorart.

FIG. 2A is a partially schematic circuit diagram of an SST systemconfigured in accordance with embodiments of the present technology.

FIG. 2B is a table illustrating changes in driver output currentscorresponding to the number of SST modules in an SST system inaccordance with embodiments of the present technology.

FIG. 3 is a partially schematic circuit diagram of an SST systemconfigured in accordance with other embodiments of the presenttechnology.

FIG. 4 is a partially schematic circuit diagram of an SST systemconfigured in accordance with further embodiments of the presenttechnology.

FIG. 5 is a schematic view of a system that includes SST modulesconfigured in accordance with embodiments of the present technology.

DETAILED DESCRIPTION

Specific details of several embodiments of self-identifying SST modulesand associated systems and methods are described below. The term “SST”generally refers to solid-state transducers that include a semiconductormaterial as the active medium to convert electrical energy intoelectromagnetic radiation in the visible, ultraviolet, infrared, and/orother spectra. For example, SSTs include solid-state light emitters(e.g., LEDs, laser diodes, etc.) and/or other sources of emission otherthan electrical filaments, plasmas, or gases. SSTs can also includesolid-state devices that convert electromagnetic radiation intoelectricity. A person skilled in the relevant art will also understandthat the technology may have additional embodiments, and that thetechnology may be practiced without several of the details of theembodiments described below with reference to FIGS. 2A-5.

FIG. 2A is a partially schematic circuit diagram of an SST system 200configured in accordance with embodiments of the present technology. TheSST system 200 can include a driver 202 operably coupled to a pluralityof SST modules (identified individually as first through fifth SSTmodules 204 a-e, respectively, and referred to collectively as SSTmodules 204). The driver 202 can include a power supply 210 and aconstant current controller 212. As shown in FIG. 2A, each of the SSTmodules 204 can include one or more SSTs 206 (illustrated as LEDs) and asense resistor 208. The SSTs 206 of the SST modules 204 can beelectrically coupled in a first parallel circuit 201 to the constantcurrent controller 212 via an SST input channel 214 a and an SST returnchannel 214 b (referred to collectively as SST channels 214). The senseresistors 208 can be electrically coupled in separate second parallelcircuit 203 to the constant current controller 212 via a sense inputchannel 216 a and a sense return channel 216 b (referred to collectivelyas sense channels 216). In operation, the constant current controller212 can use the total resistance measured across sense resistors 208 toidentify the number of SST modules 204 coupled to the driver 202 andsupply a corresponding level of current across the SSTs 206 via the SSTchannels 214.

As shown in FIG. 2A, the SST system 200 can include five SST modules 204that are coupled together in parallel via the first and second circuits201 and 203. In other embodiments, however, the SST system 200 caninclude fewer than five SST modules 204 (e.g., one SST module 204) ormore than five SST modules 204. Regardless of the number of SST modules204 in the SST system 200, the individual SST modules 204 receivesubstantially equal current inputs because they are coupled in parallelwith one another. As such, the SST system 200 can generate substantiallyuniform emissions (e.g., light) across all of the SST modules 204.

In the embodiment illustrated in FIG. 2A, each of the SST modules 204includes two SSTs 206 coupled together in series. However, in otherembodiments the individual SST modules 204 can include a single SST 206or more than two SSTs 206 (e.g., an array of SSTs 206) coupled togetherin series or in parallel. The individual SSTs 206 can include a firstsemiconductor material, an active region, and a second semiconductormaterial stacked sequentially on one another and formed using metalorganic chemical vapor deposition (“MOCVD”), molecular beam epitaxy(“MBE”), liquid phase epitaxy (“LPE”), hydride vapor phase epitaxy(“HVPE”), and/or other suitable epitaxial growth techniques known in theart. The first semiconductor material can include a P-type semiconductormaterial (e.g., a P-type gallium nitride (“P-GaN”)), and the secondsemiconductor material can include an N-type semiconductor (e.g., anN-type gallium nitride (“N-GaN”)). In selected embodiments, the firstand second semiconductor materials can individually include at least oneof gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), galliumarsenide phosphide (GaAsP), gallium (III) phosphide (GaP), zinc selenide(ZnSe), boron nitride (BN), aluminum gallium nitride (AlGaN), and/orother suitable semiconductor materials. The active region can include asingle quantum well (“SQW”), MQWs, and/or a bulk semiconductor material.The term “bulk semiconductor material” generally refers to a singlegrain semiconductor material (e.g., InGaN) with a thickness betweenapproximately 10 nanometers and approximately 500 nanometers. In certainembodiments, the active region can include an InGaN SQW, GaN/InGaN MQWs,and/or an InGaN bulk material. In other embodiments, the active regioncan include aluminum gallium indium phosphide (AlGaInP), aluminumgallium indium nitride (AlGaInN), and/or other suitable materials orconfigurations. In various embodiments, the SSTs 206 can be configuredto emit light in the visible spectrum (e.g., from about 390 nm to about750 nm), in the infrared spectrum (e.g., from about 1050 nm to about1550 nm), and/or in other suitable spectra.

Each SST module 204 can include one sense resistor 208, and all thesense resistors 208 in the SST system 200 can have at leastsubstantially similar resistances. For example, the individual senseresistors 208 may each have a resistance of 1 kΩ with a 5% tolerance. Inother embodiments, the sense resistors 208 may have higher or lowerresistances and/or lower or higher tolerances (e.g., a 1% tolerance).Because each sense resistor 208 (and therefore each SST module 204) hasa substantially identical resistance, the constant current controller212 can associate the change in sense resistance due to the addition ofa sense resistor 208 in the second parallel circuit 203 with theaddition of an SST module 204 to the SST system 200. In certain aspectsof the technology, the resistance of each sense resistor 208 may besubstantially higher than the wire, trace, and connection resistance ofthe second parallel circuit 203 such that the constant currentcontroller 212 can distinguish between the circuit resistance and theaddition or removal of a parallely coupled sense resistor 208. Forexample, the individual sense resistors 208 may have a resistance ofabout 1 kΩ or higher. In other embodiments, the individual SST modules204 may include more than one sense resistor 208, but still beconfigured such that the total sense resistance of each SST module 204in the SST system 200 is substantially similar.

The sense resistors 208 can be positioned virtually anywhere in the SSTsystem 200. For example, the sense resistors 208 can be positioned undera lens that encapsulates the SSTs 206 (e.g., the lens 36 shown in FIG.1B) or outside the lens on the same substrate as the SSTs 206. The senseresistors 208 may also be incorporated into an SST device (e.g.,including the SSTs 206) and electrically coupled (e.g., wirebonded) toan external contact pad (e.g., in a similar fashion as an embeddedelectrostatic discharge (ESD) protection diode). In other embodiments,the sense resistors 208 can also be positioned external to the array ofSSTs 206 on a printed circuit board and/or elsewhere in the SST system200.

As discussed above, the sense resistors 208 and the SSTs 206 can beelectrically coupled to the driver 202 via separate parallel circuits201, 203. The driver 202 can include one or more channels. Each channelcan have a unique sense input or, in embodiments with multi-channeldrivers, the channels can operate off of a single sense input to set thecurrent of all the channels. For example, in the embodiment illustratedin FIG. 2A, the driver 202 includes multiple channels (e.g., SST andsense channels 214 and 216) such that the constant current controller212 can use the sense input from the sense channels 216 to set thecurrent across the SST channels 214. Therefore, the sense channels 216allow the constant current controller 212 to measure changes in senseresistance across the second parallel circuit 203 (i.e., the totalresistance of the sense resistors 208 coupled in parallel), andautomatically adjust the current supplied across the SST channels 214 inresponse to the changed sense resistance. In various embodiments, thedriver 202 can include an analog or digital circuit that associates thechanges in sense resistance with a proportional current outputcorresponding to the number of SST modules 204 in the SST system 200.

The driver's power supply 210 may be configured to convert an AC inputvoltage to a DC output voltage that can drive the SST modules 204. Inother embodiments, the power supply 210 may have other suitableconfigurations, such as a DC/DC power supply. The constant currentcontroller 212 can control the level of power received from the powersupply 210 to drive the SST modules 204 at an at least substantiallyconstant level of current.

In various embodiments, the SST system 200 may further include a controlcircuit 218 (indicated by an input arrow) that is operably coupled tothe constant current controller 212. The control circuit 218 can controlthe intensity of light and/or other emissions generated by the SSTs 206(e.g., using 0-10 V DC control signals). For example, the controlcircuit 218 may use Digital Addressable Lighting Interface (DALI)dimming, Digital Multiplex (DMX) dimming, triac dimming, and/or othersuitable intensity control interfaces known to persons skilled in theart to provide emission control.

Several embodiments of the SST system 200 shown in FIG. 2A can adjustthe amount of current supplied to the SST modules 204 based on the senseresistance measured by the constant current controller 212. For example,when the first SST module 204 a is electrically coupled to the driver202, the SSTs 206 are electrically coupled to the constant currentcontroller 212 in the first circuit 201 via the SST channels 214, andthe sense resistor 208 is electrically coupled to the constant currentcontroller 212 in the second circuit 203 via the sense channels 216. Theconstant current controller 212 measures the resistance of the singlesense resistor 208 (e.g., 1 kΩ), and delivers a proportional level ofcurrent (associated with one SST module 204) to the SSTs 206 in thefirst circuit 201 via the SST channels 214. As shown in the chart inFIG. 2B, if the driver 202 has a minimum output current is 350 mA, thedriver 202 delivers 350 mA when one SST module 204 is connected to thedriver 202.

When the second SST module 204 b is connected to the driver 202, theSSTs 206 are connected in parallel with the SSTs 206 of the first SSTmodule 204 a in the first circuit 201, and the sense resistors 208 ofthe first and second SST modules 204 a and 204 b are connected inparallel in the second circuit 203. As discussed above, all of the senseresistors 208 have substantially identical resistances, and thereforethe addition of the second SST module 204 causes the sense resistancemeasured by the constant current controller 212 to decrease by half(e.g., from 1 kΩ to 500Ω). This reduction in sense resistance indicatesto the constant current controller 212 that a second SST module 204 hasbeen added to the system 200. In response, the driver 202 suppliesdouble the amount of current (e.g., 700 mA) across the SST modules 204such that two parallely coupled SST modules 204 are supplied the samelevel of current (e.g., 350 mA). Electrically coupling additional SSTmodules 204 to the driver 202 results in corresponding reductions in thesense resistance measured by the constant current controller 212, andthereby triggers proportional increases in the amount of currentdelivered to the SSTs 206 in the first circuit 201. The chart shown inFIG. 2B, for example, illustrates the incremental decreases in senseresistance and corresponding increases in driving current as eight SSTmodules are coupled to a 350 mA minimum current output driver.

As shown in FIG. 2B, the change in measured sense resistance becomesincreasingly smaller as additional SST modules 204 are added to the SSTsystem 200 because the sense resistors 208 are coupled in parallel.Accordingly, a practical limit with respect to the maximum number of SSTmodules 204 in the SST system 200 may arise based on the sensitivity ofthe constant current controller 212. For example, if the constantcurrent controller 212 has a sensitivity of 10Ω (i.e., able todistinguish between 10Ω changes in resistance), the practical limit forthe driver represented in FIG. 2B may be eight SST modules 204. In otherembodiments, the sense pin of the constant current controller 212 may bemore accurate (e.g., able to sense as little as 0.10Ω differences inresistance), and therefore more SST modules 204 may be coupled to thedriver 202. Practical limits as to the number of SST modules 204 in theSST system 200 may also arise because the maximum current that thedriver 202 can supply to the SST modules 204 may be limited.

In operation, the driver 202 can automatically adjust the drivingcurrent output for the number of SST modules 204 attached thereto basedsimply on the SST modules 204 as they are added to and/or removed fromthe second circuit 203. Accordingly, SST system manufacturers no longerneed to stock a plurality of different drivers with incrementallydiffering voltage and/or current levels (e.g., 30 V, 35V, 40V, etc) thatmust be matched to specific SST system configurations. Instead, the SSTsystem 200 allows manufacturers to stock one type of driver thatautomatically matches its current output based on the input received(i.e., the sense resistance) from the self-identifying SST modules 204as they are connected to or disconnected from the second circuit 203.The flexibility provided by the SST system 200 does not come from theaddition of expensive switching circuits, potentiometers, and/or memorycircuits to the driver 202 (e.g., as is the case in so-called“intelligent” drivers). Rather, it is the SST modules 204 that enhancethe flexibility of the SST system 200 by identifying themselves as theyare electrically coupled to and decoupled from the driver 202. Thisflexibility provided by the addition of a relatively inexpensive systemcomponent (i.e., the sense resistors 208). As such, the SST modules 204can be easily added to and removed from the system 200 to accommodatevarious different lighting or SST configurations without the additionalcost associated with intelligent drivers. Moreover, because the SSTmodules 204 are connected in parallel, they are each driven by the sameamount of current. This uniform current distribution across the currentstrings of the SST modules 204 provides for a more uniform output (e.g.,illumination) from the SSTs 206 across the SST system 200.

FIG. 3 is a partially schematic circuit diagram of an SST system 300configured in accordance with other embodiments of the presenttechnology. The SST system 300 can include features generally similar tothe features of the SST system 200 described above with reference toFIG. 2A. For example, the SST system 300 includes a driver 302 havingthe power supply 310, a constant current or voltage controller 312(“controller 312”), and an optional intensity control circuit 318. Thecontroller 312 is electrically coupled to a plurality of SST modules(identified individually as first through fifth SST modules 304 a-e,respectively, and referred to collectively as SST modules 304). As shownin FIG. 3, the individual SST modules 304 include one or more SSTs 306electrically coupled in parallel to the SST channels 314 of thecontroller 312. However, unlike the SST modules 204 shown in FIG. 2A,none of the SST modules 304 of the SST system 300 shown in FIG. 3include sense resistors. The constant current controller's sensechannels 316 therefore form an open circuit, and the controller 312detects an infinite sense resistance.

The configuration shown in FIG. 3 causes the driver 302 to operate atmaximum current output and drive the SST system 300 as a constantvoltage source. In constant voltage systems, performance can be verydependent on forward voltage variations from module 304 to module 304(e.g., changes in voltage from the first SST module 306 a to the secondSST module 306 b). However, the SST system 300 allows for at least smallforward voltage variations that do not substantially affect theuniformity of the emissions because the SST modules 306 are coupled inparallel. For example, if the first SST module 304 a operates a lowervoltage (e.g., 28 V) than the second SST module 304 b (e.g., 38 V), thefirst SST module 304 a is driven by a higher level of current than thesecond SST module 304 b due to the first SST module's inherently lowerresistance, and therefore the first and second SST modules 304 a and 304b are driven the same way. The same driver 302 can therefore be used tooperate in a constant current mode with the self-identifying SST modules204 (FIG. 2A) or in a constant voltage mode with the SST modules 304without sense resistors. Accordingly, LED luminaire manufacturers and/orother SST system manufacturers can simply stock one type of driver andtwo different types of SST modules (i.e., constant current-type modulewith a sense resistor and constant voltage-type module without a senseresistor) to create various different SST luminaires and other systemswithout having to match different drivers to the SST modules.

FIG. 4 is a partially schematic circuit diagram of an SST system 400configured in accordance with further embodiments of the presenttechnology. The SST system 400 can include features generally similar tothe features of the SST system 200 described above with reference toFIG. 2A. For example, the SST system 400 can include a driver 402 havinga power supply 410 and a controller 412 (e.g., a constant currentcontroller) operably coupled to a plurality of SST modules (identifiedindividually as first through fifth SST modules 404 a-e, respectively,and referred to collectively as SST modules 404). The SST modules 404each include one or more SSTs 406 electrically coupled in a parallelcircuit to the controller 412 via SST channels 414, and a sense resistor408 electrically coupled in a separate parallel circuit to thecontroller 412 via sense channels 416. In operation, the controller 412can detect the sense resistance across the sense circuit and supply aproportional level of current to the SSTs 406 via the SST channels 414.

In the embodiment illustrated in FIG. 4, the SST system 400 furtherincludes an additional or supplemental resistor 420 that is not a partof an SST module, but is coupled in parallel with the sense resistors408 (e.g., between the controller 412 and the sense resistor 408 of thefirst SST module 404 a). The supplemental resistor 420 decreases thetotal sense resistance seen by the constant current controller 212, andtherefore causes the driver 402 to supply a corresponding increase inthe level of current supplied to the SSTs 406 via the SST channels 414.For example, if the supplemental resistor 420 has a resistanceequivalent to that of the other sense resistors 408 in the system 400,the controller 412 will interpret the addition of the supplementalresistor 420 as an additional SST module and increase the currentdelivered to the SSTs 406 accordingly. Because the SSTs 406 are coupledin parallel across the SST channels 414, the current increase initiatedby the supplemental resistor 420 is spread evenly across the SST modules404. Therefore, without hindering the uniformity of the SST output, thesupplemental resistor 420 can be used to manipulate the sense resistanceof the SST system 400, and thereby tune the current output to generate adesired level of SST emissions (e.g., a predetermined lumen output).

In various embodiments, the supplemental resistor 420 can be selectedbased on the resistance necessary to achieve a predetermined increase incurrent output, and then the supplemental resistor 420 can be coupledbetween the sense channels 416 as shown in FIG. 4. In other embodiments,the supplemental resistor 420 have an arbitrary resistance, and theoperating parameters (e.g., resistance) of the supplemental resistor 420can be manipulated after the supplemental resistor 420 is attached inparallel with the sense resistors 408. For example, after electricallycoupling the supplemental resistor 420 in the parallel circuit, theresistor material can be ablated using laser trimming techniques knownin the art to adjust the resistance of the supplemental resistor 420.Current can be supplied to the SSTs 406 before, after, and/or duringlaser trimming to monitor the effect the changes in resistance have onthe SST emissions. As such, the supplemental resistor 420 can be finelytuned to cause a precise level of current to be supplied to the SSTs 406for a desired emission output (e.g., a specific lumen output). Infurther embodiments, the supplemental resistor 420 can be a variableresistor and/or other suitable resistor that can be used as an intensitycontroller to control the constant current controller's current output.

Any one of the SST systems described above with reference to FIGS. 2A-4can be incorporated into any of a myriad of larger and/or more complexsystems, a representative example of which is system 500 shownschematically in FIG. 5. The system 500 can include one or more SSTmodules 510, a driver 520, a processor 530, and/or other subsystems orcomponents 540. The resulting system 500 can perform any of a widevariety of functions, such as backlighting, general illumination, powergenerations, sensors, and/or other suitable functions. Accordingly,representative systems 500 can include, without limitation, hand-helddevices (e.g., mobile phones, tablets, digital readers, and digitalaudio players), lasers, photovoltaic cells, remote controls, computers,and appliances. The system 500 can also be configured as an LEDluminaire that replaces fluorescent and/or other lighting structures.Components of the system 500 may be housed in a single unit ordistributed over multiple, interconnected units (e.g., through acommunications network). The components of the system 500 can alsoinclude local and/or remote memory storage devices, and any of a widevariety of computer readable media.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. For example, the SST systems shown in FIGS. 2A, 3 and 4 eachinclude five SST modules. However, in other embodiments SST systems inaccordance with the present technology can include fewer than five SSTmodules or more than five SST modules depending upon the applicationand/or any practical limitations of the sense resistors. Certain aspectsof the new technology described in the context of particular embodimentsmay also be combined or eliminated in other embodiments. Additionally,while advantages associated with certain embodiments of the newtechnology have been described in the context of those embodiments,other embodiments may also exhibit such advantages, and not allembodiments need necessarily exhibit such advantages to fall within thescope of the technology. Accordingly, the disclosure and associatedtechnology can encompass other embodiments not expressly shown ordescribed herein.

I claim:
 1. A method of operating a solid-state transducer (SST) system,the method comprising: coupling at least one SST module and asupplemental resistor to a driver, wherein— each SST module includes atleast one SST and at least one sense resistor, the sense resistors ofthe SST modules and the supplemental resistor are coupled in parallel toa sense channel of the driver, and the SSTs of the SST modules arecoupled in parallel to an SST channel of the driver; detecting a senseresistance across the sense channel; and supplying, via the driver, acurrent across the SST channel based on the sense resistance.
 2. Themethod of claim 1 wherein the sense resistance comprises a first senseresistance and the current comprises a first current, the method furthercomprising: coupling an additional SST module to the driver; detecting asecond resistance across the sense channel, wherein the secondresistance is different from the first sense resistance; and supplying,via the driver, a second current across the SST channel based on thesecond resistance, wherein the second current is different from thefirst current.
 3. The method of claim 2 wherein the second senseresistance is less than the first sense resistance and wherein thesecond current is greater than the first current.
 4. The method of claim2 wherein— the additional SST module includes an additional SST and anadditional sense resistor, and coupling the additional SST module to thedriver comprises electrically coupling the additional sense resistor tothe sense channel in parallel with the sense resistors of the other SSTmodules and the supplemental resistor and coupling the additional SST tothe SST channel in parallel with the other SSTs of the other SSTmodules.
 5. The method of claim 4 wherein the additional sense resistorhas a resistance value within 5% of at least one of the other senseresistors.
 6. The method of claim 1 wherein— the sense resistancecomprises a first sense resistance, the current comprises a firstcurrent, each of the sense resistors in the SST modules have resistancessubstantially equal to a first resistance value, and the supplementalresistor has a resistance equal to a second resistance value, the methodfurther comprising: modulating the supplemental resistor to move theresistance of the supplemental resistor to a third resistance valuedifferent from the second resistance value, detecting a second senseresistance across the sense channel, wherein the second sense resistanceis different from the first sense resistance; and supplying, via thedriver, a second current across the SST channel based on the secondsense resistance, wherein the second current is different from the firstcurrent.
 7. A solid-state transducer (SST) system, comprising: aplurality of SST modules, the individual SST modules including at leastone SST and at least one sense resistor; a supplemental resistor; and adriver electrically coupled to the plurality of SST modules and to thesupplemental resistor, wherein— the SSTs of the SST modules areelectrically coupled together in a first parallel circuit, the senseresistors of the SST modules and the supplemental resistor areelectrically coupled together in a second parallel circuit, the firstand second parallel circuits are electrically coupled to separatechannels of the driver, and the driver is configured to deliver currentto the first parallel circuit proportional to a resistance measured fromthe second parallel circuit.
 8. The SST system of claim 7 wherein thesupplemental resistor is configured to modulate an emission output ofthe SSTs.
 9. The SST system of claim 7 wherein the second parallelcircuit has a circuit resistance corresponding to wire, trace, andconnection resistance in the second parallel circuit, and wherein eachof the sense resistors has a substantially higher resistance value thanthe circuit resistance.
 10. The SST system of claim 7 wherein the senseresistor in each SST module has a resistance of at least 1 kΩ.
 11. TheSST system of claim 7 wherein the sense resistors of the individual SSTmodules have sense resistance values within 5% of each other.
 12. TheSST system of claim 11 wherein the supplemental resistor has asupplemental resistance value substantially equivalent to the senseresistance values of the sense resistors of the individual SST modules.13. The SST system of claim 11 wherein the supplemental resistor has asupplemental resistance value substantially different from the senseresistance values of the sense resistors of the individual SST modules.14. The SST system of claim 7 wherein the supplemental resistorcomprises a variable resistor.
 15. The SST system of claim 7 wherein theSSTs in the first parallel circuit are configured to emit an amount oflight proportional to the current delivered to the first parallelcircuit from the driver.
 16. A method of forming a solid-statetransducer (SST) system, comprising: electrically coupling at least oneSST module to a driver having an SST channel and a sense channel,wherein each of the at least one SST modules comprises at least one SSTand at least one sense resistor, and wherein electrically coupling theat least one SST module to the driver comprises— coupling each of theSSTs to the SST channel in a first parallel circuit, and coupling eachof the sense resistors to the sense channel in a second parallelcircuit; electrically coupling a supplemental resistor to the secondparallel circuit such that the supplemental resistor is coupled inparallel with each of the sense resistors, wherein the supplementalresistor is not part of an SST module; detecting a sense resistanceacross the sense channel; providing a current to the SSTs in the firstparallel circuit via the SST channel, wherein the current is based onthe sense resistance; monitoring emission outputs from the SSTs; andmodulating the supplemental resistor in response to determining that theemission outputs are sufficiently different from a predeterminedemission output.
 17. The method of claim 16, wherein the senseresistance comprises a first sense resistance and the current comprisesa first current, the method further comprising: after modulating thesupplemental resistor, detecting a second sense resistance differentfrom the first resistance across the sense channel; and providing asecond current to the SSTs in the first parallel circuit via the SSTchannel, wherein the second current is based on the second senseresistance and is different from the first current.
 18. The method ofclaim 16 wherein modulating the supplemental resistor comprises lasertrimming the supplemental resistor.
 19. The method of claim 16 whereinmodulating the supplemental resistor comprises changing a resistancevalue of the supplemental resistor.
 20. The method of claim 16 whereinindividual of the sense resistors have resistance values within 5% ofone another.